Mr Bowles says 204 people have used their repatriation package to start a small business.

AAP: Lukas Coch. File photo

The Immigration Department has outlined a breakdown of the $1.5 billion price tag for running the nation's asylum seeker detention network.

The department's secretary, Martin Bowles, told Senate Estimates the broad cost of operating the detention network at this point of the financial year falls just shy of $1.5 billion.

He says the cost, as of the end of April, includes $686 million for service provision by SERCO, $103 million for the lease of some detention facilities, $53 million for the Red Cross and $107 million for freight, charter and other travel costs.

"The health services (cost) around $206 million and the rest is odds and sods," he said.

Mr Bowles says the figures includes Christmas Island, but not the costs associated with asylum seekers placed within the community.

The Immigration Department says 231 asylum seekers have accepted taxpayer-funded repatriation packages to return to their home country this financial year.

The packages are worth up to $US4,000 each and are provided as a mixture of cash and services.

Asylum seekers receiving the packages have returned to Sri Lanka, Iran, Vietnam, Pakistan, Afghanistan and Iraq.

Mr Bowles told the Senate Estimates hearing 204 people have used their repatriation package to start a small business.

"Some people end up with tools to be a tradesman or a motorbike to be a delivery person or all sorts of different things like that," he said.

"And again, if someone comes up with a good idea about how they might be able to sustain themselves back home, we will contemplate how that actually works."

Asylum seekers not explicitly offered legal advice

But Greens Senator Sarah Hanson-Young raised concerns at the hearing that some asylum seekers are being 'screened out' before they have a chance to get advice about lodging a refugee claim.

Senator Hanson-Young asked the Department of Immigration whether asylum seekers are offered access to a lawyer for the screening interview that helps determine whether they have a valid asylum claim.

The Department of Immigration confirmed asylum seekers are not explicitly offered the opportunity to have a lawyer present during the initial screening process for their claim.

The department's chief lawyer, Vicky Parker, said asylum seekers are not told that they are able to request legal advice.

"If they seek advice, Senator [Hanson-Young], then we facilitate that contact with a legal advisor of their choice," Ms Parker said.

"We provide them with a telephone book and access to a telephone, and an interpreter if necessary, I believe."

More than 1,900 asylum seekers have arrived by boat since the Federal Government put in place its "no advantage" principle in August last year.

Australian authorities assisted an asylum seeker boat believed to be carrying 95 passengers and three crew members north-west of Christmas Island on Sunday.

The group has been transferred to Christmas Island for initial security and health checks.